This study is in response to the program announcement, Health Risk Reduction: Community-Based Strategies, and is an essential step in developing culturally relevant interventions to promote positive sexual health practices and outcomes among homeless adolescents. The specific aims are to 1) describe the sexual health practices, including prevalence and incidence of STD testing, diagnosis, and treatment as well as the prevalence and incidence of immunizations for hepatitis B, of homeless adolescents; 2) examine the relationships among variables in the conceptual model of sexual health practices: sociodemographics, sexual history, culture of homelessness, cognitive perceptual factors, behavioral factors, and individual sexual health practices of homeless adolescents; 3) determine the indirect effects of sociodemographics, sexual history, and culture of homelessness, and the direct effects of cognitive perceptual factors and behavioral factors on individual sexual health practices of homeless adolescents; and 4) explore with homeless adolescents the feasibility of developing culturally relevant interventions to promote positive sexual practices in this population through (a) focus groups that explore their perceptions of factors that are culturally relevant, and (b) comparing characteristics of those subjects who remain connected to the project site for periods of 3, 6, 9, and 12 months and characteristics of those who leave the area during these time intervals. A convenience sample of 460 homeless youth will be surveyed to describe their sexual health practices and to examine relationships among theoretical variables through structural equation modeling. A subsample of 40 homeless youth will participate in focus groups to provide their perspectives on community-based interventions to reduce the risk of sexually transmitted diseases (STDs) that would be culturally relevant and feasible for them. The expected outcomes of the study are the refinement of a theoretical model of sexual health practices that will provide a framework for interventions to reduce the prevalence and incidence of STDs in vulnerable homeless adolescents.